Control valve with semi-automatically indexed valve element

ABSTRACT

A return spring yieldingly resists movement of a control valve element out of neutral to a first working position. Detent means is automatically operable to releasably hold the valve element in said first working position as well as in a flow reversing second working position between neutral and said first working position. In each working position, the valve element is released from the detent means whenever supply fluid pressure rises to a predetermined kick-out value by means of detent disabling means which is cooperable with the return spring to automatically effect stepwise return motion of the valve element from said first to said second working position thereof and then from said second working position back to neutral.

United States Patent 1 Wilke CONTROL VALVE WITH SEMI-AUTOMATICALLY INDEXED VALVE ELEMENT [75] Inventor: Raud A. Wilke, Milwaukee, Wis.

[73] Assignee: Koehring Company, Milwaukee,

Wis.

[22] Filed: Aug. 2, 1971 {21] Appl. No.: 167,926

[52] US. Cl. 137/106, 91/356, 137/624.27,

[51] Int. Cl. ..F15b 11/15 [58] Field of Search 91/356, 358 A;

[ 5 6] References Cited UNITED STATES PATENTS 3,170,377 2/1965 Herpich et al. 91/356 X 3,132,668 5/1964 Stacey 137/624.27

3,568,717 3/1971 Plate et al.. 137/624.27

2,848,014 8/1958 Tennis 137/624.27

4/1966 Tennis 137/624.27 X

[ June 12, 1973 3,263,574 8/1966 Tennis 137/625.69 X 3,618,634 11/1971 Nelson 137/624.27

Primary Examiner-Alan Cohan Assistant Examiner-Gerald A. Michalsky Attorneylra Milton Jones [5 7] ABSTRACT disabling means which is cooperable with the return,

spring to automatically effect stepwise return motion of the valve element from said first to said second working position thereof and then from said second working position back to neutral.

4 Claims, 4 Drawing Figures it E; 2 5.; 28 2c! 3 34- 29 11 1 Ill CONTROL VALVE WITH SEMI-AUTOMATICALLY INDEXED VALVE ELEMENT This invention relates to control valves for fluid pressure actuatable systems, and it has more particular reference to control valves which are intended for semiautomatic control of reversible fluid motors such as double acting hydraulic cylinders.

To that end, it is an object of this invention to provide a control valve which, upon initial manually effected actuation to cause operation of a fluid motor in one direction, is thereafter automatically operable to first effect motor operation in the opposite direction and to finally bring the motor to rest.

More specifically, it is a purpose of the invention to provide a control valve for a reversible fluid motor such as a double acting cylinder, which can be actuated in consequence of a manual act to initiate a power stroke of the cylinder, and which is thereafter automatically operable to effect the retraction stroke of the cylinder and cessation of cylinder operation upon completion of the retraction stroke. 7

Hence, it can be said that it is a general object of the invention to provide a semi-automatic cylinder control valve with a valve element which can be manually actuated to initiate a work cycle and which is thereafter automatically indexed to effect completion of the cycle.

With these observations and objectives in mind, the manner in which the invention achieves its purpose will be appreciated from the following description and the accompanying drawings, which exemplify the invention, it being understood that changes may be made in the specific apparatus disclosed herein without depart ing from the essentials of the invention set forth in the appended claims.

The accompanying drawings illustrate two complete examples of embodiments of the invention constructed according to the best modes so far devised for the practical application of the principles thereof, and in which:

FIG. I is a more or less diagrammatic sectional view of a hydraulic control valve embodying the principles of this invention, showing the valve element thereof in neutral;

FIG. 2 is a view similar to FIG. 1, showing the valve element moved to an actuated position to initiate a work cycle;

FIG. 3, is a view similar to FIG. 2 but showing the valve element in a position reversing the operation of the governed cylinder; and

FIG. 4 is a view similar to FIG. 1, illustrating a holdin-neutral control valve embodying this invention.

Referring now more particularly to the accompanying drawings, the numeral 5 generally designates the body of a control valve for governing the operation'of a reversible fluid motor such as the hydraulic cylinder 6.

The valve is provided with an elongated valve element 7 of the type commonly referred to as a spool, and which normally occupies a non-operating or neutral position such as seen in FIG. 1, to which it is urged by a return spring S. The spool is movable against the force of its return spring to each of a pair of operating positions (FIGS. 2 and 3) to effect reversal of the connections of the cylinder ports 8 and 9 with pressure fluid supply and return means.

The valve body is provided with a bore 10 in which the valve spool 7 is axially slidably received, and a number of passages all of which intersect the bore at different locations along its length. These latter include a pair of service passages 11 and 12 which are shown connected with motor ports 8 and 9, respectively; pressure fluid supply means comprising a pair of inlet connected passages 13 and 14 at opposite sides of an outlet connected passage 15, and a high pressure bridge 16 also connected with the inlet and having branches 17 and 18 located inwardly adjacent to the service passages 11 and 12 respectively, but outwardly of the inlet connected passages 13 and 14; and fluid return means comprising a low pressure bridge 19 having branches 20 and 21 located outwardly adjacent to the service passages 11 and 12, respectively.

In a single spool valve such as shown, the upstream branches 13 and 14 of the fluid supply means are communicated with the inlet of the valve to receive pump output fluid, while the downstream branch 15 is connected to the valve outlet. The low pressure bridge is also connected to the valve outlet, as by a passageway 22.

In the neutral position of the valve shown in FIG. 1, circumferential grooves in the valve spool connect both upstream branches 13 and 14 of the supply passage with the outlet connected downstream branch 15 of the supply passage. Hence, pump fluid entering the inlet of the valve flows freely through the supply passage means to the outlet of the valve for return to tank. Also in this neutral position of the valve spool, both service passages 11 and 12 are communicated with their adjacent exhaust passage branches 20 and 21 respectively. It can thus be said that the spool places the valve in float in its neutral position, although it is by no means essential to provide such a float-in-neutral feature. A hold in neutral spool 7' such as seen in FIG. 4 can also be used without departing from the spirit of the invention.

' The valve spool 7 is movable to each of a pair of operating positions located different distances to the right of netural, against the force of its return spring S, to provide for operation of the cylinder in opposite directions. In a first one of these operating positions of the spool more distant from neutral, (FIG.2), the spool lands close off flow of pump fluid to the downstream branch 15 of the supply passage means and divert pump output fluid through a load holding check valve 24 to the high pressure bridge 16. Supply fluid thus delivered into the bridge passage flows through its left hand branch 17 to the bore 10 and to the service passage 11 through a circumferential groove 25 in the spool.

As mentioned hereinbefore, service passage 11 is connected to cylinder port 8, in the head end of the cylinder 6, so that pressure fluid flowing thereinto effects extension of the piston rod 26, to initiate the power stroke of the cylinder. Fluid expelled from the rod end of the cylinder enters service passage 12 and flows to the return passage branch 21 then in communication therewith for return to tank.

The operating position of the spool thus described is defined by automatically releasable detent means 28 of the type disclosed in the patent to F. H. Tennis U.S. Pat. No. 2,848,014, issued Aug. 19, 1958. The detent means is mounted within a tubular housing 29 which is fixed to the valve body and encircles the projecting right hand end portion of the valve spool. The encircled portion of the spool is hollow and its wall has one or more holes therein located in a common radial plane, to receive detent balls 30. A plunger 31 slidably received in the hollow end portion of the spool is biased by a spring 32 toward the valve body, to bring a cam surface thereon into spreading engagement with the balls and thus cause the same to be yieldingly urged outwardly against the inner wall of the housing 29. The balls can thus be snapped into axially spaced cavities 33, 34 or 35 in the housing wall, depending upon the position of the valve spool, at such times as the balls are brought into register with those cavities.

In the neutral positionof the spool, the detent balls are held yieldingly projected into the cavity 33 closest to the valve body. In that operating position of the spool at which it effects extension of the piston rod 26, the detent balls are engaged in the cavity 35 farthest from the valve body.

It is to be understood, of course, that the detent means can be readily overcome by force applied to the spool to shift the same out of its neutral position to its operating position seen in FIG. 2; and that the detent means is capable of holding the spool in either its FIG. 2 or FIG. 3 positions, against the force of the return spring S.

As described in the aforesaid Tennis patent, the detent means can be disabled automatically to provide for release of the valve spool therefrom at times when pressure of supply fluid flowing to the cylinder rises to a predetermined kick-out value. For this purpose, the left hand end of plunger 31 is subjected either to the pressure of fluid obtaining in the inlet connected supply passage branches, or in the high pressure bridge 16, or in whichever service passage is communicated with the supply passage by the valve element.

As shown, the valve spool is provided with an elongated axial bore 36 which opens at one end to the hollow end portion of the spool through a valve seat 37, and at its other end to a crossbore 38 in the spool. The crossbore 38 registers with the inlet connected branch 13 of the supply passage in the rod extending operating position of the spool;

When the piston rod 26 reaches the end of its powerstroke, fluid pressure quickly rises in branch 13 of the supply passage to a predetermined kick-out value capable of lifting relief valve 40 off of its seat 37, so that pressure fluid from branch 13 of the supply passage can flow into the hollow end portion of the spool at the left end of plunger 31 and drive the latter to the right, against the force of its spring 32. This effects removal of the outward bias on the detent balls and release of the spool therefrom for return movement toward neutral, under the. influence of its return spring S.

It should be understood, of course, that the detent kick-out mechanism comprising the relief valve 40 and plunger 31 will be operated to effect disablement of the detent means and release of the valve spool for return movement anytime the predetermined kick-out pressure is reached in cylinder 6, and accordingly in the fluid supply passage means of the control valve. In other words, the kick-out pressure may be attained before the piston rod 26 of cylinder 6 reaches the end of its power stroke, depending upon the magnitude of the work load imposed upon the cylinder.

Return motion of the valve spool from its piston rod extending position is interrupted at the second operating position of the spool, at a location between neutral and its first described operating position, at the time the detent balls snap into the cavity 34 under the action of the cam surface on plunger 31. It will be appreciated, of course, that the plunger 31 of the detent kickout mechanism will be advanced toward the valve body by its spring 32, to an operative ball engaging and spreading position, as soon as the valve spool has been returned a distance toward neutral only far enough to carry the crossbore 38 out of registry with the branch 13 of the supply passage. At that time, the relief valve 40 recloses under spring force, and fluid ahead of plunger 31 is free to exhaust to the branch 21 of the return passage means through the clearances around the plunger and the exterior of the hollow end portion of the spool.

In its second operating position, the valve spool effects reversal of the connections between the service passages and the supply and exhaust passage means. Thus, pressure fluid diverted to the high pressure bridge 16 in the second operating position of the valve spool will flow to service passage 12 and to the rod end of the cylinder 6, while fluid expelled from the head end of the cylinder will return to service passage 11 for flow to the exhaust passage branch 20 then in communication therewith.

The detent kick-out mechanism, comprising relief valve 40 and cam plunger 31, will be again actuated when the pressure in the rod end of the cylinder rises to the aforesaid predetermined kick-out value, as for example, when the piston rod reaches the end of its retraction stroke, to thus effect momentary disablement of the detent means and release of the valve spool for return to its neutral position.

The detent balls will be propelled outwardly into the cavity 33 when the balls are brought into registry therewith, so as to bring the valve spool to rest in its neutral position.

It will be seen, therefore, that the control valve operates in a semi-automatic fashion. That is to say, performance of a manual act is necessary to effect movement of its spool out of neutral to its first described operating position to cause extension of the piston rod in cylinder 6 and thus initiate a work stroke of the cylinder; while the spool will be automatically stepwise returned or indexed to neutral, with a pause at its second described operating position to effect retracting motion of the piston rod. A work cycle is completed, of course, when the valve spool returns its neutral position, from which it can be'again advanced to its operating position located more distant from neutral to initiate another work cycle.

As mentioned earlier, the valve spool need not necessarily connect the service passages to the exhaust passage in its neutral position. The hold-in-neutral type of spool 7 shown in FIG. 4 is capable of effecting semiautomatic operation of the cylinder in the same way as described above. In this case, however, the supply passage has been shown as comprising single upstream and downstream branches 113 and 115, respectively. The spool 7' is grooved so as to communicate the supply branches 113 and 115 in neutral, but to block communication therebetween in both operating positions of the spool and thus pressurize the high pressure bridge 16.

From the foregoing description, together with the accompanying drawings, it will be apparent to those skilled in the art that this invention provides a novel control valve by which the work cycle of a hydraulic cylinder or other fluid motor can be initated manually and concluded automatically.

Those skilled in the art will appreciate that the invention can be embodied in forms other than as herein disclosed for purposes of illustration.

The invention is defined by the following claims:

I claim:

1. A control valve having first and second service passages and a valve element to govern communication thereof with supply and return passage means, said control valve being chaacterized by the following:

A. the valve element having a neutral position toward which it is biased and in which position it communicates both service passages with the return passage means, and having a pair of working positions at the same side of neutral to effect reversal of the connections of the service passages with said supply and return passage means;

B. detent means operable in each of said working positions of the valve element to releasably hold the same against return motion toward its neutral position;

C. and fluid pressure actuatable detent kick-out means operable in each of said working positions of the valve element to effect momentary release thereof from the detent means in response to rise in the pressure of fluid in the supply passage means to a predetermined value.

2. A control valve having a valve element movable counter to the action of a return spring from a neutral position to first and second detent defined working positions to connect either of a pair of service passages with pressure fluid supply passage means and the other with return passage means, characterized by:

A. said second and first working positions of the valve element being respectively located greater distances in the same direction from its neutral position;

B. fluid pressure actuatable detent kick-out means operable in each of said working positions of the valve element, in response to attainment of a predetermined high pressure in the supply passage means, to momentarily render the detent means ineffective and thereby effect stepwise motion of the valve element to its neutral position from said first working position thereof under the action of said return spring thereon;

C. and both service passages being communicated with the return passage means by the valve element in said neutral position thereof.

3. A control valve having a pair of service passages and supply and return passage means, characterized by the following:

A. a valve element to reverse the connections of the service passages with the supply and return passage means in two operating positions thereof located different distances in the same direction from a non-operating position thereof at which it communicates both service passages with the return passage means;

B. return spring means acting on the valve element and yieldingly resisting movement thereof in said direction;

C. detent means defining said operating positions of the valve element,

1. said detent means providing for manually effected actuation of the valve element to that one of its said operating positions more distant from neutral;

2. and said detent means being operable to arrest spring produced return motion of the valve element at that one of its said operating positions closer to neutral;

D. and detent kick-out means actuable in consequence of rise in the pressure of fluid in the supply passage means to a predetermined value to effect momentary release of the valve element from the detent means in each of said working positions of the valve element.

4. A control valve having a valve element movable in one direction, counter to the action of a return spring, from a neutral position to each of a pair of working positions at the same side of neutral to selectively communicate either of a pair of service passages with pressure fluid supply passage means while concurrently connecting the non-selected service passage with fluid return means, characterized by:

A. detent means for releasably holding the valve element in its working position more distant from neutral and operable to arrest spring propelled return motion of the valve element at the other of its working positions;

B. detent kick-out means actuatable by supply fluid at an abnormally high pressure to effect release of the detent means in each of said working positions of the valve element;

C. and means for activating said kick-out means in each of said working positions of the valve element comprising a passageway in the valve element which communicates with a different passage in the valve containing supply pressure fluid. 

1. A control valve having first and second service passages and a valve element to govern communication thereof with supply and return passage means, said control valve being chaacterized by the following: A. the valve element having a neutral position toward which it is biased and in which position it communicates both service passages with the return passage means, and having a pair of working positions at the same side of neutral to effect reversal of the connections of the service passages with said supply and return passage means; B. detent means operable in each of said working pOsitions of the valve element to releasably hold the same against return motion toward its neutral position; C. and fluid pressure actuatable detent kick-out means operable in each of said working positions of the valve element to effect momentary release thereof from the detent means in response to rise in the pressure of fluid in the supply passage means to a predetermined value.
 2. and said detent means being operable to arrest spring produced return motion of the valve element at that one of its said operating positions closer to neutral; D. and detent kick-out means actuable in consequence of rise in the pressure of fluid in the supply passage means to a predetermined value to effect momentary release of the valve element from the detent means in each of said working positions of the valve element.
 2. A control valve having a valve element movable counter to the action of a return spring from a neutral position to first and second detent defined working positions to connect either of a pair of service passages with pressure fluid supply passage means and the other with return passage means, characterized by: A. said second and first working positions of the valve element being respectively located greater distances in the same direction from its neutral position; B. fluid pressure actuatable detent kick-out means operable in each of said working positions of the valve element, in response to attainment of a predetermined high pressure in the supply passage means, to momentarily render the detent means ineffective and thereby effect stepwise motion of the valve element to its neutral position from said first working position thereof under the action of said return spring thereon; C. and both service passages being communicated with the return passage means by the valve element in said neutral position thereof.
 3. A control valve having a pair of service passages and supply and return passage means, characterized by the following: A. a valve element to reverse the connections of the service passages with the supply and return passage means in two operating positions thereof located different distances in the same direction from a non-operating position thereof at which it communicates both service passages with the return passage means; B. return spring means acting on the valve element and yieldingly resisting movement thereof in said direction; C. detent means defining said operating positions of the valve element,
 4. A control valve having a valve element movable in one direction, counter to the action of a return spring, from a neutral position to each of a pair of working positions at the same side of neutral to selectively communicate either of a pair of service passages with pressure fluid supply passage means while concurrently connecting the non-selected service passage with fluid return means, characterized by: A. detent means for releasably holding the valve element in its working position more distant from neutral and operable to arrest spring propelled return motion of the valve element at the other of its working positions; B. detent kick-out means actuatable by supply fluid at an abnormally high pressure to effect release of the detent means in each of said working positions of the valve element; C. and means for activating said kick-out means in each of said working positions of the valve element comprising a passageway in the valve element which communicates with a different passage in the valve containing supply pressure fluid. 